1. Field of the Invention
The present invention relates to a solid-state image pickup device, an optical apparatus including the solid-state image pickup device, a signal processing apparatus to which the optical apparatus is connected, and a signal processing system including the optical apparatus and the signal processing apparatus. In particular, the present invention relates to a solid-state image pickup device, an optical apparatus, a signal processing apparatus, and a signal processing system capable of modulating an externally input light beam using a pixel signal read from the solid-state image pickup device and outputting a modulated light signal.
2. Description of the Related Art
As the processing speed and the packaging density of circuit boards have increased, problems of a signal delay and the occurrence of EMI (electromagnetic interference) have arisen. Accordingly, optical interconnection technology that solves signal delay and signal degradation occurring in electrical interconnections and electromagnetic interference noise radiated from electrical interconnections and that allows high-speed transmission has received a significant amount of attention recently.
As one of high-speed signal transmission technologies using a light beam in a board, a technology called optical interconnection has been developed (refer to, for example, Japanese Unexamined Patent Application Publication No. 2004-219882). In Japanese Unexamined Patent Application Publication No. 2004-219882, a two-dimensional optical waveguide layer, a semiconductor laser that can switch an oscillation mode, and an optical path switching structure that switches an optical path of a light beam emitted from a semiconductor laser are used.
The optical path switching structure changes an output angle in an optical waveguide layer in accordance with switching of the oscillation mode of a semiconductor laser so that an output beam propagates in the optical waveguide layer. In this way, a propagation state of a light transmission signal in the two-dimensional optical waveguide layer can be selected. Accordingly, the layout of a light-emitting element and a light receiving element can be freely determined and, therefore, the light signal transmission configuration can be flexibly reconfigured.
In particular, recently, flat displays have been increased in body size and screen size and, therefore, signals have been delayed. Accordingly, a signal transmission technology using a light beam is one of the solutions. The above-described optical interconnection technology can be applied to TFTs used for driving a flat display.
In addition, a technology in which a solid-state image pickup device is incorporated in a lens unit that is removable from a camera body and a signal output from the solid-state image pickup device can be transmitted to the camera body using a light beam has been developed (refer to, for example, Japanese Unexamined Patent Application Publication No. 2006-196972).